Processes for making ponatinib and intermediates thereof

ABSTRACT

Methods are disclosed for making 3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-[4-[(4-methylpiperazin-1-yl)methyl]-3-(trifluoromethyl)phenyl]benzamide, intermediates and pharmaceutically acceptable salts thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/178,813 filed Jun. 10, 2016 and claims the benefit of each of U.S.Provisional Patent Application Ser. No. 62/174,083 filed Jun. 11, 2015,U.S. Provisional Patent Application Ser. No. 62/175,721 filed Jun. 15,2015, and U.S. Provisional Patent Application Ser. No. 62/204,571 filedAug. 13, 2015, the entireties of which are incorporated herein byreference.

FIELD OF THE INVENTION

The presently disclosed subject matter provides novel syntheticapproaches to make3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-[4-[(4-methylpiperazin-1-yl)methyl]-3-(trifluoromethyl)phenyl]benzamide,intermediates and pharmaceutically acceptable salts thereof.

BACKGROUND

3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-[4-[(4-methylpiperazin-1-yl)methyl]-3-(trifluoromethyl)phenyl]benzamide,also known as ponatinib, is a multi-targeted tyrosine-kinase inhibitorused in the treatment of chronic myeloid leukemia (CML) and Philadelphiachromosome positive (Ph+) acute lymphoblastic leukemia (ALL). Some formsof CML, those that have the T315I mutation, are resistant to currenttherapies such as imatinib. Ponatinib was designed to be effectiveagainst these types of tumors.

SUMMARY OF THE INVENTION

The presently disclosed processes involve a novel synthetic approach tomake ponatinib in a simple and easily scalable process, overcoming thedrawbacks of prior art processes.

In one embodiment a method is disclosed for the production of ponatinibhydrochloride of the formula (I)

In accordance with one or more embodiments, a method of making ponatinibor a pharmaceutically acceptable salt thereof, includes the steps of:reacting 3-iodo-4-methylbenzoyl chloride with a solution of4-amino-2-(trifluoromethyl)benzaldehyde to obtainN-(4-formyl-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide; addinga base, an iodide reagent and a catalyst to a solution ofN-(4-formyl-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide toobtain a reaction mixture, and adding 3-ethynylimidazo[1,2-b]pyridazineto the reaction mixture to obtainN-(4-formyl-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide;reacting a solution ofN-(4-formyl-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamidewith sodium borohydride to obtainN-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide;reacting a solution ofN-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamidewith a chloride to obtainN-(4-(chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide;and reacting a solution ofN-(4-(chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamidewith N-methylpiperazine to obtain3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl)benzamide.

Ponatinib hydrochloride may be obtained by the further step ofsaturating a solution of the3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl)benzamidewith HCl gas.

Suitable solvents for dissolving 4-amino-2-(trifluoromethyl)benzaldehyde include but are not limited to dichloromethane (MDC) andethyl acetate. In one embodiment the solvent is MDC.

Suitable solvents for dissolvingN-(4-formyl-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide includebut are not limited to dimethylformamide (DMF), dimethyl sulfoxide(DMSO), tetrahydrofuran (THF) and acetonitrile. Suitable bases foraddition to a solution ofN-(4-formyl-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide includebut are not limited to N,N-diisopropylethylamine (DIPEA), triethylamine(TEA) and diethylamine (DEA). In one embodiment the base is DIPEA.

An example of a suitable iodide reagent for addition to a solution ofN-(4-formyl-3-(trifluoromethyl) phenyl)-3-iodo-4-methylbenzamide is CuI.

Suitable catalysts for addition to a solution ofN-(4-formyl-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide includebut are not limited to PdCl₂(PPh₃)₂, Pd(PPh₃)₄, Pd(dppe)Cl, Pd(dppp)Cl₂,and Pd(dppf)Cl₂. In one embodiment the catalyst is PdCl₂(PPh₃)₂.

Exemplary chloride compounds for reacting with a solution ofN-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamideinclude but are not limited to phosphoryl chloride, thionyl chloride,oxalyl chloride, cyanuric chloride and phosphorous pentachloride. Incertain embodiments the chloride compound is phosphoryl chloride orthionyl chloride.

In accordance with some embodiments the4-amino-2-(trifluoromethyl)benzaldehyde may be obtained by reacting asolution of 4-nitro-2-(trifluoromethyl)benzaldehyde in AcOH with iron.

In still further embodiments, methods of making ponatinib or apharmaceutically acceptable salt thereof, may include the steps ofreactingN-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamidewith a chloride compound to obtainN-(4-(chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide;and adding N-methylpiperazine to a solution ofN-(4-(chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamideto obtain3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl)benzamide.

Ponatinib hydrochloride may be obtained by the further step ofsaturating a solution of the3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl)benzamidewith HCl gas.

Exemplary chloride compounds include but are not limited to phosphorylchloride, thionyl chloride, oxalyl chloride, cyanuric chloride andphosphorous pentachloride. In certain embodiments the chloride isphosphoryl chloride or thionyl chloride.

In further embodiments, the step of reactingN-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamidewith a chloride compound to obtainN-(4-(chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamidemay include adding thionyl chloride to a solution ofN-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide.

In still further embodiments, the step of reactingN-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamidewith a chloride compound to obtainN-(4-(chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamidemay include adding N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo [1,2-b] pyridazin-3-ylethynyl)-4-methylbenzamide to asolution of dimethylformamide (DMF) and POCl₃.

In yet still further embodiments, theN-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamidemay be obtained by a process which includes dissolving4-(3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamido)-2-(trifluoromethyl)benzyl acetate in a solvent and then adding a base.

Suitable solvents include but are not limited to tetrahydrofuran (THF)and 2-methyl tetrahydrofuran (2-Me THF). In some embodiments the solventis THF. Suitable bases include but are not limited to NaOH, KOH andLiOH. In some embodiments the base is NaOH.

In yet still further embodiments, theN-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamidemay be obtained by a process which includes dissolvingN-(4-formyl-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamidein a solvent and then adding sodium borohydride.

In accordance with other embodiments, theN-(4-(hydroxymethyl)-3-(trifluoromethyl) phenyl)-3-(imidazo [1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide may be obtained by a processincluding dissolving N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide in a solvent to form a solution, addinga base, an iodide reagent and a catalyst to the solution, andsubsequently adding 3-ethynylimidazo[1,2-b] pyridazine to the solution.Suitable solvents for dissolvingN-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide include but are not limited to DMF andDMSO. In one embodiment the solvent is DMF. Suitable bases include butare not limited to DIPEA, TEA and DEA. In one embodiment the base isDIPEA. An exemplary suitable iodide reagent for addition to a solutionof N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide is CuI.

Suitable catalysts for addition to a solution ofN-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide include but are not limited toPdCl₂(PPh₃)₂, Pd(PPh₃)₄, Pd(dppe)Cl, Pd(dppp)Cl₂, and Pd(dppf)Cl₂. Inone embodiment the catalyst is PdCl₂(PPh₃)₂.

In yet further embodiments, the N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide may be obtained by a process whichincludes combining (4-amino-2-(trifluoromethyl) phenyl) methanol indichloromethane and adding pyridine, and subsequently adding3-iodo-4-methylbenzoyl chloride solution in dichloromethane.

Given above is a simplified summary in order to provide a basicunderstanding of some aspects described herein. This summary is not anextensive overview, and is not intended to identify key/criticalelements or to delineate the scope of the claimed subject matter.

DETAILED DESCRIPTION OF THE INVENTION

The following is a detailed description of the invention provided to aidthose skilled in the art in practicing the present invention. Those ofordinary skill in the art may make modifications and variations in theembodiments described herein without departing from the spirit or scopeof the present invention. Unless otherwise defined, all technical andscientific terms used herein have the same meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. The terminology used in the description of the invention hereinis for describing particular embodiments only and is not intended to belimiting of the invention. All publications, patent applications,patents, figures and other references mentioned herein are expresslyincorporated by reference in their entirety.

The following description describes novel synthetic schemes whichprovide economical and easily scalable methods for making the drugponatinib at a commercial scale.

The following embodiments of novel Schemes I-IV are provided.

EXAMPLES AND EXPERIMENTS—SCHEME II Example 11-(Bromomethyl)-4-nitro-2-(trifluoromethyl)benzene

A suspension of 2-methyl-5-nitrobenzotrifluoride (3.90 g, 19 mmol),N-bromosuccinimide (NBS, 3.56 g, 20 mmol),2,2′-azobis(2-methylpropionitrile) (AIBN, 94 mg, 0.6 mmol) in CCl₄ (40mL) was refluxed under nitrogen for 16 h. HPLC indicated ca. 50%conversion. More NBS (10 mmol) and AIBN (0.6 mmol) were added, and themixture was refluxed for another 14 h. HPLC indicated ca. 80%conversion. The reaction mixture was cooled down, and the solid wasfiltered off and washed with ethyl acetate. The combined filtrate waswashed with aq. NaHCO₃, dried over Na₂SO₄, filtered, concentrated onrotovap and further dried under vacuum to afford a solid.

Example 2 4-Nitro-2-(trifluoromethyl)benzyl acetate

A suspension of 1-(Bromomethyl)-4-nitro-2-(trifluoromethyl)benzene (1mmol), potassium acetate (1.2 mmol) in DMF was stirred at RT for 3 hr.After completion of the reaction, the reaction mixture was diluted withwater and extracted in ethyl acetate thrice. The combined organic layerwas washed with water, dried over Na₂SO₄, filtered, and evaporated onrotovap to afford yellow coloured viscous liquid.

Example 3 4-Amino-2-(trifluoromethyl)benzyl acetate

4-Nitro-2-(trifluoromethyl)benzyl acetate (1 mmol) was dissolved inAcOH. Iron powder (5 mmol) was added portionwise to the mixture. Thereaction mixture was stirred at RT for 2-3 hrs. At the completion of thereaction pH of the reaction mass was adjusted up to 10-12 by adding sat.Na₂CO₃ solution at 0-10° C. and extracted with ethyl acetate thrice. Thecombined organic layer was washed with water, dried over Na₂SO₄,filtered, and evaporated on rotovap to obtain solid material.

Example 4 4-(3-Iodo-4-methylbenzamido)-2-(trifluoromethyl)benzyl acetate

4-amino-2-(trifluoromethyl)benzyl acetate (1 mmol) was dissolved in MDC.Triethylamine (1.5 mmol) was added to the mixture. The mixture wascooled to 0° C. Then, solution of 3-iodo-4-methylbenzoyl chloride in MDCwas added drop wise to the mixture. Temperature was maintained at 0-5°C. during addition. The reaction mass was stirred at 0-10° C. for about1 hr, and then at RT for half an hour. At the completion of the reactionthe reaction mass was poured into water and stirred for about 20 min.Then the organic layer was separated, washed with saturated Na₂CO₃solution on cooling, dried over Na₂SO₄, filtered, and evaporated onrotovap to obtain solid material.

Example 54-(3-(Imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamido)-2-(trifluoromethyl)benzyl acetate

4-(3-iodo-4-methylbenzamido)-2-(trifluoromethyl)benzyl acetate wasdissolved in DMF, DIPEA, CuI and Pd(PPh₃)₄ were added and the mixturewas stirred under nitrogen. The mixture was stirred for around 10-20min., then 3-ethynylimidazo[1,2-b]pyridazine was added to the mixture.The reaction mixture was stirred at RT for about 2-3 hrs. undernitrogen. Reaction progress was monitored by TLC. At the completion ofthe reaction the reaction mass was poured into water and filtered. Thenthe residue was taken in methanol and stirred for 10 min. and filtered.Filtrate was evaporated under vacuum to obtain solid material.

Example 6N-(4-(Hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide

4-(3-(Imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamido)-2-(trifluoromethyl)benzyl acetate (1 mmol) was dissolved in THF (20 vol.) and then 1M NaOHsolution (16 mmol) was added thereto at RT. The reaction mixture wasstirred for 2-3 hr and then diluted with ethyl acetate and the aq. layerextracted with ethyl acetate. Then organic layer was dried over Na₂SO₄,filtered, and evaporated on rotovap to obtain residue.

Example 7N-(4-(Chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide

N-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide(1 mmol) was taken in MDC, thionyl chloride (4 mmol) was added to it andthe mixture was stirred for 3-4 hrs. At the completion of the reaction,solvent and thionyl chloride were evaporated under vacuum at 50-60° C.to obtain free solid material.

Example 83-(Imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl)benzamide

N-(4-(chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide(1 mmol) was taken in MDC, N-methylpiperazine (1.2 mmol) was added andthe mixture was stirred for about 3-4 hrs. At the completion of thereaction the reaction mass was poured into water and extracted with MDC.The organic layer was separated, dried with anhydrous sodium sulphateand evaporated to obtain solid material.

Example 93-(Imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl)benzamidehydrochloride

3-(Imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl)benzamide(1 mmol) was dissolved in methanol (5 vol.) and saturated with HCl gasat 0-5° C. and stirred for 1-2 hrs. The solid was filtered, washed withmethanol, suction dried and dried at 50-60° C. to obtain hydrochloridesalt.

EXAMPLES AND EXPERIMENTS—SCHEMES I AND III Example 10(4-Nitro-2-(trifluoromethyl)phenyl)methanol

4-Nitro-2-(trifluoromethyl) benzoic acid (1 mmol) was taken up in THF(10 vol.) and NaBH₄ (2.95 mmol) was added portionwise. The reactionmixture was cooled to 0-10° C., then boron trifluoride etherate (2.84mmol) was added dropwise and the mixture stirred overnight at RT. Themixture was cooled to 0° C. and combined with 1M NaOH solution withstirring. Then THF was evaporated and the crude product was extractedwith ethyl acetate. The organic layer was washed with sat. NaClsolution, dried on Na₂SO₄, filtered, and evaporated to obtain theresidue.

Example 11 4-Nitro-2-(trifluoromethyl)benzaldehyde

A suspension of (4-Nitro-2-(trifluoromethyl)phenyl)methanol (1 mmol),MnO₂ (10 wt) in CHCl₃ was refluxed for 3-4 hrs. At the completion of thereaction, the reaction mass was filtered, filtrate was evaporated todryness.

Example 12 4-Amino-2-(trifluoromethyl)benzaldehyde

4-Nitro-2-(trifluoromethyl)benzaldehyde (1 mmol) was dissolved in AcOH.Iron powder (5 mmol) was added portionwise to the mixture. The reactionmixture was stirred at RT for 2-3 hrs. At the completion of the reactionpH of the reaction mass was adjusted up to 10-12 by adding sat. Na₂CO₃solution at 0-10° C. and extracted with ethyl acetate thrice. Thecombined organic layer was washed with water, dried over Na₂SO₄,filtered, and evaporated on rotovap to obtain solid material.

Example 13N-(4-Formyl-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide

4-Amino-2-(trifluoromethyl)benzaldehyde (1 mmol) was dissolved in MDC,and triethylamine (1.5 mmol) was added to it. The mixture was cooled to15-25° C. Then, a solution of 3-iodo-4-methylbenzoyl chloride in MDC wasadded drop-wise to the mixture. Temperature was maintained at 15-25° C.during addition. The reaction mass was stirred at 15-25° C. for about 1hr. and then at RT for half an hour. At the completion of the reactionthe reaction mass was poured into water and stirred for about 20 min.Then the organic layer was separated, washed with sat. Na₂CO₃ solutionon cooling, dried over Na₂SO₄, filtered, and evaporated on rotovap toobtain solid material.

Example 14N-(4-Formyl-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide

N-(4-formyl-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide (1 mmol)was dissolved in DMF, DIPEA, CuI and PdCl₂(PPh₃)₂ were added to themixture and the mixture was stirred under nitrogen for around 10-20 min.Then 3-ethynylimidazo[1,2-b]pyridazine (2 mmol) was added to themixture. The reaction mixture was stirred at RT for about 2-3 hrs. undernitrogen. Reaction progress was monitored by TLC. At the completion ofthe reaction the reaction mass was poured into water and filtered. Thenthe residue (filter cake) was taken in methanol and stirred for 10 min.and filtered. Filtrate was evaporated under vacuum to obtain solidmaterial.

Example 15N-(4-(Hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide

N-(4-formyl-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide(1 mmol) was dissolved in ethanol and then sodium borohydride (0.3 mmol)was added to it at 0-5° C. The reaction mixture was stirred at 0-5° C.for 2-3 hr and then at RT for half an hour. At the completion of thereaction the reaction mass was poured into water. White coloured solidsprecipitated out were filtered, washed with water and dried undervacuum.

Example 16N-(4-(Chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide

N-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide(1 mmol) was taken in MDC, thionyl chloride (4 mmol) was added to it at25-30° C. and the mixture was stirred for 3-4 hrs. At the completion ofthe reaction, solvent and thionyl chloride were evaporated under vacuumat 50-60° C. to obtain free solid material.

Example 173-(Imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl)benzamide

N-(4-(chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide(1 mmol) was taken in MDC, N-methylpiperazine (1.2 mmol) was added tothe mixture and the mixture was stirred for about 3-4 hrs. At thecompletion of the reaction the reaction mass was poured into water andextracted with MDC. The organic layer was separated, dried withanhydrous sodium sulphate and evaporated to obtain solid material.

Example 18 3-(Imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl) benzamide hydrochloride

3-(Imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl) phenyl) benzamide (1 mmol) was dissolved inmethanol (5 vol.) and saturated with HCl gas at 0-5° C. and stirred for1-2 hrs. The solid was filtered, washed with methanol, suction dried anddried at 50-60° C. to obtain the hydrochloride salt.

EXAMPLES AND EXPERIMENTS—SCHEME IV Example 19(4-Nitro-2-(trifluoromethyl)phenyl) methanol

4-Nitro-2-(trifluoromethyl) benzoic acid (1 mmol) was taken up in THF(10 vol.) and NaBH₄ (2.95 mmol) was added portion wise. The reactionmixture was cooled to 0-10° C., then boron difluoride etherate (2.84mmol) was added dropwise and the mixture stirred overnight at RT. Themixture was cooled to 0° C. and combined with 1M NaOH solution withstirring. Then THF was evaporated and the crude product was extractedwith ethyl acetate. The organic layer was washed with sat. NaClsolution, dried on Na₂SO₄, filtered, and evaporated to obtain theresidue.

Example 20 (4-amino-2-(trifluoromethyl) phenyl) methanol

A suspension of (4-Nitro-2-(trifluoromethyl) phenyl) methanol (1 mmol),Raney nickel (30% wet) in methanol was refluxed for 3-4 hrs. At thecompletion of the reaction, the reaction mass was filtered throughcelite and the filtrate concentrated to a thick mass, and subsequentlythe solid was crystallized using hexane.

Example 21 3-Iodo-4-methylbenzoyl chloride

3-Iodo-4-methylbenzoic acid (1 mmol) was dissolved in dichloromethaneand then oxalyl chloride charged in the vessel at 0 to 50. A catalyticamount of dimethylformamide was charged in the vessel. The reaction masstemperature was raised to 25-30° C. and maintained for 16-18 hrs. Aftercompletion of the reaction, the reaction mass was distilled to a thickoily mass which was subsequently used for further reaction.

Example 22 N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide

(4-amino-2-(trifluoromethyl) phenyl) methanol (1 mmol) was taken indichloromethane & then pyridine (3 mmol) was added to obtain a clearsolution. Then was added 3-iodo-4-methylbenzoyl chloride solution indichloromethane slowly at 0-5° C. The reaction was allowed to come at25-30° C., and maintained for 2-3 hrs. After completion of reaction, theproduct was isolated as a solid after addition of water to the reactionmass.

Example 23 N-(4-(hydroxymethyl)-3-(trifluoromethyl) phenyl)-3-(imidazo[1,2-b] pyridazin-3-ylethynyl)-4-methylbenzamide

N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-3-iodo-4-methylbenzamide (1 mmol) was dissolved in DMF, DIPEA,CuI and PdCl₂(PPh₃)₂ were added to the mixture and the mixture wasstirred under nitrogen for around 10-20 min., then3-ethynylimidazo[1,2-b] pyridazine (2 mmol) was added to the mixture.The reaction mixture was stirred at RT for about 2-3 hrs. undernitrogen. Reaction progress was monitored by TLC. At the completion ofthe reaction the reaction mass was poured into water and filtered. Thenthe residue (filter cake) was purified from acetonitrile to get thesolid product.

Example 24 N-(4-(chloromethyl)-3-(trifluoromethyl) phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide

N-(4-(hydroxymethyl)-3-(trifluoromethyl) phenyl)-3-(imidazo [1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide (1 mmol) was charged to asolution of dimethylformamide & POCl₃ (Vilsmeier reagent) slowly at 0-5°C. and maintained for 4-5 hrs at 25-30° C. After completion of reaction,the reaction mass was charged to process water to get solid product.This solid product was purified in methanolic HCl as HCl salt, which wassubsequently used for further stages.

Example 25 3-(Imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl) phenyl) benzamide

N-(4-(chloromethyl)-3-(trifluoromethyl) phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide (1 mmol) was taken indichloromethane (30.0 volumes). N-methylpiperazine (3.0 volumes) wasadded to the mixture and the mixture was stirred for about 10-12 hrs. Atthe completion of the reaction the reaction mass was quenched by addinga saturated solution of sodium bicarbonate. The organic layer washedwith process water and further treated with charcoal and dried oversodium sulphate. Finally, the organic layer was evaporated to dryness toget solid product as ponatinib base (ponatinib technical).

Example 26 3-(Imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl) benzamide hydrochloride

3-(Imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl)benzamide(1 mmol) was charged to methanol (4.0 volumes) and acetonitrile (1.0volume) and then methanolic HCl solution was slowly added by adjustingpH of reaction mass to 4.0-4.5 to get the desired monohydrochloride. Thereaction mass was seeded with the desired polymorph Form-I and thendegassed to reduce the excess acidity. Finally the product was isolatedafter filtration. The solid was dried at 50-55° C. under vacuum 720-750mm of Hg to get residual solvents as per ICH limits. This processovercomes the earlier prior art processes of making Form-I in which theresidual solvents are always seen above the limits.

Although the compositions and methods of the present disclosure havebeen described with reference to exemplary embodiments thereof, thepresent disclosure is not limited thereby. Indeed, the exemplaryembodiments are implementations of the disclosed compositions andmethods are provided for illustrative and non-limitative purposes.Changes, modifications, enhancements and/or refinements to the disclosedsystems and methods may be made without departing from the spirit orscope of the present disclosure. Accordingly, such changes,modifications, enhancements and/or refinements are encompassed withinthe scope of the present invention.

What is claimed is:
 1. A method of making ponatinib or a pharmaceutically acceptable salt thereof, comprising the steps of: reacting N-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide with a chloride compound to obtain N-(4-(chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide; and adding N-methylpiperazine to a solution of N-(4-(chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide to obtain 3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl)benzamide.
 2. The method of claim 1 comprising the further step of saturating a solution of the 3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methyl-N-(4-((4-methylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl)benzamide with HCl gas to form ponatinib hydrochloride.
 3. The method of claim 1 wherein the chloride compound is selected from the group consisting of phosphoryl chloride, thionyl chloride, oxalyl chloride, cyanuric chloride and phosphorous pentachloride.
 4. The method of claim 1 wherein the step of reacting N-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide with a chloride compound to obtain N-(4-(chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide comprises adding thionyl chloride to a solution of N-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide.
 5. The method of claim 1 wherein the step of reacting N-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide with a chloride compound to obtain N-(4-(chloromethyl)-3-(trifluoromethyl)phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide comprises adding N-(4-(hydroxymethyl)-3-(trifluoromethyl) phenyl)-3-(imidazo [1,2-b] pyridazin-3-ylethynyl)-4-methylbenzamide to a solution of dimethylformamide and POCl₃.
 6. The method of claim 1 wherein the N-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide is obtained by a process comprising dissolving 4-(3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamido)-2-(trifluoromethyl) benzyl acetate in a solvent and then adding a base.
 7. The method of claim 6 wherein the solvent is selected from the group consisting of tetrahydrofuran (THF) and 2-methyl tetrahydrofuran (2-Me THF).
 8. The method of claim 6 wherein the base is selected from the group consisting of NaOH, KOH and LiOH.
 9. The method of claim 1 wherein the N-(4-(hydroxymethyl)-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide is obtained by a process comprising dissolving N-(4-formyl-3-(trifluoromethyl)-phenyl)-3-(imidazo[1,2-b]pyridazin-3-ylethynyl)-4-methylbenzamide in a solvent and then adding sodium borohydride.
 10. The method of claim 1 wherein the N-(4-(hydroxymethyl)-3-(trifluoromethyl) phenyl)-3-(imidazo [1,2-b] pyridazin-3-ylethynyl)-4-methylbenzamide is obtained by a process comprising dissolving N-(4-(hydroxymethyl)-3-(trifluoromethyl) phenyl)-3-iodo-4-methylbenzamide in a solvent to form a solution, adding a base, an iodide reagent and a catalyst to the solution, and subsequently adding 3-ethynylimidazo[1,2-b] pyridazine to the solution.
 11. The method of claim 10 wherein the base is selected from the group consisting of N,N-diisopropylethylamine (DIPEA), triethyl amine (TEA), and diethylamine (DEA).
 12. The method of claim 10 wherein the iodide reagent is CuI.
 13. The method of claim 10 wherein the catalyst is selected from the group consisting of PdCl₂(PPh₃)₂, Pd(PPh₃)₄, Pd(dppe)Cl, Pd(dppp)Cl₂, and Pd(dppf)Cl₂.
 14. The method of claim 10 wherein the N-(4-(hydroxymethyl)-3-(trifluoromethyl) phenyl)-3-iodo-4-methylbenzamide is obtained by a process comprising combining (4-amino-2-(trifluoromethyl) phenyl) methanol in dichloromethane and adding pyridine, and subsequently adding 3-iodo-4-methylbenzoyl chloride solution in dichloromethane. 